Integrated Drive Electronics (IDE) is a standard electronic interface used between a computer motherboard bus and disk storage devices. IDE has been adopted as a standard by American National Standards Institute (ANSI), whereby the ANSI designation for IDE is Advanced Technology Attachment (ATA). IDE/ATA also refers to the electronic protocol used by computers or host devices to transfer data to/from data storage devices. There are two data transfer methods used in IDE: Programmed Input/Output (PIO) and Direct Memory Access (DMA). In PIO mode, the data transfer is initiated and performed by the host device or processor. In DMA mode, data transfer is controlled by signals for handshaking between the host device and the data storage device.
When proprietary information is kept in storage media where physical access control cannot be assured, data encryption and decryption provides a mechanism for protecting data from unauthorized access. Data may be cryptographically protected by encrypting data as it is sent from a host device to a data storage device, and decrypting the stored data as it is retrieved from the data storage device upon request by the host device.
In a conventional data relay approach, data is transferred via an IDE bridge or interface placed in series between a host and a data storage device. This type of data transfer traditionally requires that the IDE interface implement an IDE controller supporting full ATA protocol on each side of the IDE interface for data buffering/dataflow control. The IDE interface simultaneously plays the role of a virtual host device with the data storage device and the role of a virtual data storage device with the host device during IDE/ATA data transfer. The problem with the data relay approach is that the IDE interface needs to implement large data buffers to maintain dataflow control. Such large data buffers are often implemented on an IDE application specific integrated circuit (ASIC) using costly static random-access memory (SRAM) macros or the like, which results in high chip manufacturing costs.